/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:        arm_fir_q15.c
*
* Description:  Q15 FIR filter processing function.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
*
* Version 0.0.5  2010/04/26
* 	 incorporated review comments and updated with latest CMSIS layer
*
* Version 0.0.3  2010/03/10
*    Initial version
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupFilters
 */

/**
 * @addtogroup FIR
 * @{
 */

/**
 * @brief Processing function for the Q15 FIR filter.
 * @param[in] *S points to an instance of the Q15 FIR structure.
 * @param[in] *pSrc points to the block of input data.
 * @param[out] *pDst points to the block of output data.
 * @param[in]  blockSize number of samples to process per call.
 * @return none.
 *
 *
 * \par Restrictions
 *  If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE
 *	In this case input, output, state buffers should be aligned by 32-bit
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function is implemented using a 64-bit internal accumulator.
 * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result.
 * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format.
 * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved.
 * After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits.
 * Lastly, the accumulator is saturated to yield a result in 1.15 format.
 *
 * \par
 * Refer to the function <code>arm_fir_fast_q15()</code> for a faster but less precise implementation of this function.
 */

#ifndef ARM_MATH_CM0

/* Run the below code for Cortex-M4 and Cortex-M3 */

#ifndef UNALIGNED_SUPPORT_DISABLE


void arm_fir_q15(
    const arm_fir_instance_q15* S,
    q15_t* pSrc,
    q15_t* pDst,
    uint32_t blockSize)
{
	q15_t* pState = S->pState;                     /* State pointer */
	q15_t* pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
	q15_t* pStateCurnt;                            /* Points to the current sample of the state */
	q15_t* px1;                                    /* Temporary q15 pointer for state buffer */
	q15_t* pb;                                     /* Temporary pointer for coefficient buffer */
	q31_t x0, x1, x2, x3, c0;                      /* Temporary variables to hold SIMD state and coefficient values */
	q63_t acc0, acc1, acc2, acc3;                  /* Accumulators */
	uint32_t numTaps = S->numTaps;                 /* Number of taps in the filter */
	uint32_t tapCnt, blkCnt;                       /* Loop counters */


	/* S->pState points to state array which contains previous frame (numTaps - 1) samples */
	/* pStateCurnt points to the location where the new input data should be written */
	pStateCurnt = &(S->pState[(numTaps - 1u)]);

	/* Apply loop unrolling and compute 4 output values simultaneously.
	 * The variables acc0 ... acc3 hold output values that are being computed:
	 *
	 *    acc0 =  b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0]
	 *    acc1 =  b[numTaps-1] * x[n-numTaps] +   b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1]
	 *    acc2 =  b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] +   b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2]
	 *    acc3 =  b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps]   +...+ b[0] * x[3]
	 */

	blkCnt = blockSize >> 2;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* Copy four new input samples into the state buffer.
		 ** Use 32-bit SIMD to move the 16-bit data.  Only requires two copies. */
		*__SIMD32(pStateCurnt)++ = *__SIMD32(pSrc)++;
		*__SIMD32(pStateCurnt)++ = *__SIMD32(pSrc)++;

		/* Set all accumulators to zero */
		acc0 = 0;
		acc1 = 0;
		acc2 = 0;
		acc3 = 0;

		/* Initialize state pointer of type q15 */
		px1 = pState;

		/* Initialize coeff pointer of type q31 */
		pb = pCoeffs;

		/* Read the first two samples from the state buffer:  x[n-N], x[n-N-1] */
		x0 = _SIMD32_OFFSET(px1);

		/* Read the third and forth samples from the state buffer: x[n-N-1], x[n-N-2] */
		x1 = _SIMD32_OFFSET(px1 + 1u);

		px1 += 2u;

		/* Loop over the number of taps.  Unroll by a factor of 4.
		 ** Repeat until we've computed numTaps-4 coefficients. */
		tapCnt = numTaps >> 2;

		while(tapCnt > 0u) {
			/* Read the first two coefficients using SIMD:  b[N] and b[N-1] coefficients */
			c0 = *__SIMD32(pb)++;

			/* acc0 +=  b[N] * x[n-N] + b[N-1] * x[n-N-1] */
			acc0 = __SMLALD(x0, c0, acc0);

			/* acc1 +=  b[N] * x[n-N-1] + b[N-1] * x[n-N-2] */
			acc1 = __SMLALD(x1, c0, acc1);

			/* Read state x[n-N-2], x[n-N-3] */
			x2 = _SIMD32_OFFSET(px1);

			/* Read state x[n-N-3], x[n-N-4] */
			x3 = _SIMD32_OFFSET(px1 + 1u);

			/* acc2 +=  b[N] * x[n-N-2] + b[N-1] * x[n-N-3] */
			acc2 = __SMLALD(x2, c0, acc2);

			/* acc3 +=  b[N] * x[n-N-3] + b[N-1] * x[n-N-4] */
			acc3 = __SMLALD(x3, c0, acc3);

			/* Read coefficients b[N-2], b[N-3] */
			c0 = *__SIMD32(pb)++;

			/* acc0 +=  b[N-2] * x[n-N-2] + b[N-3] * x[n-N-3] */
			acc0 = __SMLALD(x2, c0, acc0);

			/* acc1 +=  b[N-2] * x[n-N-3] + b[N-3] * x[n-N-4] */
			acc1 = __SMLALD(x3, c0, acc1);

			/* Read state x[n-N-4], x[n-N-5] */
			x0 = _SIMD32_OFFSET(px1 + 2u);

			/* Read state x[n-N-5], x[n-N-6] */
			x1 = _SIMD32_OFFSET(px1 + 3u);

			/* acc2 +=  b[N-2] * x[n-N-4] + b[N-3] * x[n-N-5] */
			acc2 = __SMLALD(x0, c0, acc2);

			/* acc3 +=  b[N-2] * x[n-N-5] + b[N-3] * x[n-N-6] */
			acc3 = __SMLALD(x1, c0, acc3);

			px1 += 4u;

			tapCnt--;

		}


		/* If the filter length is not a multiple of 4, compute the remaining filter taps.
		 ** This is always be 2 taps since the filter length is even. */
		if((numTaps & 0x3u) != 0u) {
			/* Read 2 coefficients */
			c0 = *__SIMD32(pb)++;

			/* Fetch 4 state variables */
			x2 = _SIMD32_OFFSET(px1);

			x3 = _SIMD32_OFFSET(px1 + 1u);

			/* Perform the multiply-accumulates */
			acc0 = __SMLALD(x0, c0, acc0);

			px1 += 2u;

			acc1 = __SMLALD(x1, c0, acc1);
			acc2 = __SMLALD(x2, c0, acc2);
			acc3 = __SMLALD(x3, c0, acc3);
		}

		/* The results in the 4 accumulators are in 2.30 format.  Convert to 1.15 with saturation.
		 ** Then store the 4 outputs in the destination buffer. */

#ifndef ARM_MATH_BIG_ENDIAN

		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc0 >> 15), 16), __SSAT((acc1 >> 15), 16), 16);
		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc2 >> 15), 16), __SSAT((acc3 >> 15), 16), 16);

#else

		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc1 >> 15), 16), __SSAT((acc0 >> 15), 16), 16);
		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc3 >> 15), 16), __SSAT((acc2 >> 15), 16), 16);

#endif /*      #ifndef ARM_MATH_BIG_ENDIAN       */



		/* Advance the state pointer by 4 to process the next group of 4 samples */
		pState = pState + 4;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = blockSize % 0x4u;

	while(blkCnt > 0u) {
		/* Copy two samples into state buffer */
		*pStateCurnt++ = *pSrc++;

		/* Set the accumulator to zero */
		acc0 = 0;

		/* Initialize state pointer of type q15 */
		px1 = pState;

		/* Initialize coeff pointer of type q31 */
		pb = pCoeffs;

		tapCnt = numTaps >> 1;

		do {

			c0 = *__SIMD32(pb)++;
			x0 = *__SIMD32(px1)++;

			acc0 = __SMLALD(x0, c0, acc0);
			tapCnt--;
		} while(tapCnt > 0u);

		/* The result is in 2.30 format.  Convert to 1.15 with saturation.
		 ** Then store the output in the destination buffer. */
		*pDst++ = (q15_t)(__SSAT((acc0 >> 15), 16));

		/* Advance state pointer by 1 for the next sample */
		pState = pState + 1;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* Processing is complete.
	 ** Now copy the last numTaps - 1 samples to the satrt of the state buffer.
	 ** This prepares the state buffer for the next function call. */

	/* Points to the start of the state buffer */
	pStateCurnt = S->pState;

	/* Calculation of count for copying integer writes */
	tapCnt = (numTaps - 1u) >> 2;

	while(tapCnt > 0u) {

		/* Copy state values to start of state buffer */
		*__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
		*__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;

		tapCnt--;

	}

	/* Calculation of count for remaining q15_t data */
	tapCnt = (numTaps - 1u) % 0x4u;

	/* copy remaining data */
	while(tapCnt > 0u) {
		*pStateCurnt++ = *pState++;

		/* Decrement the loop counter */
		tapCnt--;
	}
}

#else /* UNALIGNED_SUPPORT_DISABLE */

void arm_fir_q15(
    const arm_fir_instance_q15* S,
    q15_t* pSrc,
    q15_t* pDst,
    uint32_t blockSize)
{
	q15_t* pState = S->pState;                     /* State pointer */
	q15_t* pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
	q15_t* pStateCurnt;                            /* Points to the current sample of the state */
	q63_t acc0, acc1, acc2, acc3;                  /* Accumulators */
	q15_t* pb;                                     /* Temporary pointer for coefficient buffer */
	q15_t* px;                                     /* Temporary q31 pointer for SIMD state buffer accesses */
	q31_t x0, x1, x2, c0;                          /* Temporary variables to hold SIMD state and coefficient values */
	uint32_t numTaps = S->numTaps;                 /* Number of taps in the filter */
	uint32_t tapCnt, blkCnt;                       /* Loop counters */


	/* S->pState points to state array which contains previous frame (numTaps - 1) samples */
	/* pStateCurnt points to the location where the new input data should be written */
	pStateCurnt = &(S->pState[(numTaps - 1u)]);

	/* Apply loop unrolling and compute 4 output values simultaneously.
	 * The variables acc0 ... acc3 hold output values that are being computed:
	 *
	 *    acc0 =  b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0]
	 *    acc1 =  b[numTaps-1] * x[n-numTaps] +   b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1]
	 *    acc2 =  b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] +   b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2]
	 *    acc3 =  b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps]   +...+ b[0] * x[3]
	 */

	blkCnt = blockSize >> 2;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* Copy four new input samples into the state buffer.
		 ** Use 32-bit SIMD to move the 16-bit data.  Only requires two copies. */
		*pStateCurnt++ = *pSrc++;
		*pStateCurnt++ = *pSrc++;
		*pStateCurnt++ = *pSrc++;
		*pStateCurnt++ = *pSrc++;


		/* Set all accumulators to zero */
		acc0 = 0;
		acc1 = 0;
		acc2 = 0;
		acc3 = 0;

		/* Typecast q15_t pointer to q31_t pointer for state reading in q31_t */
		px = pState;

		/* Typecast q15_t pointer to q31_t pointer for coefficient reading in q31_t */
		pb = pCoeffs;

		/* Read the first two samples from the state buffer:  x[n-N], x[n-N-1] */
		x0 = *__SIMD32(px)++;

		/* Read the third and forth samples from the state buffer: x[n-N-2], x[n-N-3] */
		x2 = *__SIMD32(px)++;

		/* Loop over the number of taps.  Unroll by a factor of 4.
		 ** Repeat until we've computed numTaps-(numTaps%4) coefficients. */
		tapCnt = numTaps >> 2;

		while(tapCnt > 0) {
			/* Read the first two coefficients using SIMD:  b[N] and b[N-1] coefficients */
			c0 = *__SIMD32(pb)++;

			/* acc0 +=  b[N] * x[n-N] + b[N-1] * x[n-N-1] */
			acc0 = __SMLALD(x0, c0, acc0);

			/* acc2 +=  b[N] * x[n-N-2] + b[N-1] * x[n-N-3] */
			acc2 = __SMLALD(x2, c0, acc2);

			/* pack  x[n-N-1] and x[n-N-2] */
#ifndef ARM_MATH_BIG_ENDIAN
			x1 = __PKHBT(x2, x0, 0);
#else
			x1 = __PKHBT(x0, x2, 0);
#endif

			/* Read state x[n-N-4], x[n-N-5] */
			x0 = _SIMD32_OFFSET(px);

			/* acc1 +=  b[N] * x[n-N-1] + b[N-1] * x[n-N-2] */
			acc1 = __SMLALDX(x1, c0, acc1);

			/* pack  x[n-N-3] and x[n-N-4] */
#ifndef ARM_MATH_BIG_ENDIAN
			x1 = __PKHBT(x0, x2, 0);
#else
			x1 = __PKHBT(x2, x0, 0);
#endif

			/* acc3 +=  b[N] * x[n-N-3] + b[N-1] * x[n-N-4] */
			acc3 = __SMLALDX(x1, c0, acc3);

			/* Read coefficients b[N-2], b[N-3] */
			c0 = *__SIMD32(pb)++;

			/* acc0 +=  b[N-2] * x[n-N-2] + b[N-3] * x[n-N-3] */
			acc0 = __SMLALD(x2, c0, acc0);

			/* Read state x[n-N-6], x[n-N-7] with offset */
			x2 = _SIMD32_OFFSET(px + 2u);

			/* acc2 +=  b[N-2] * x[n-N-4] + b[N-3] * x[n-N-5] */
			acc2 = __SMLALD(x0, c0, acc2);

			/* acc1 +=  b[N-2] * x[n-N-3] + b[N-3] * x[n-N-4] */
			acc1 = __SMLALDX(x1, c0, acc1);

			/* pack  x[n-N-5] and x[n-N-6] */
#ifndef ARM_MATH_BIG_ENDIAN
			x1 = __PKHBT(x2, x0, 0);
#else
			x1 = __PKHBT(x0, x2, 0);
#endif

			/* acc3 +=  b[N-2] * x[n-N-5] + b[N-3] * x[n-N-6] */
			acc3 = __SMLALDX(x1, c0, acc3);

			/* Update state pointer for next state reading */
			px += 4u;

			/* Decrement tap count */
			tapCnt--;

		}

		/* If the filter length is not a multiple of 4, compute the remaining filter taps.
		 ** This is always be 2 taps since the filter length is even. */
		if((numTaps & 0x3u) != 0u) {

			/* Read last two coefficients */
			c0 = *__SIMD32(pb)++;

			/* Perform the multiply-accumulates */
			acc0 = __SMLALD(x0, c0, acc0);
			acc2 = __SMLALD(x2, c0, acc2);

			/* pack state variables */
#ifndef ARM_MATH_BIG_ENDIAN
			x1 = __PKHBT(x2, x0, 0);
#else
			x1 = __PKHBT(x0, x2, 0);
#endif

			/* Read last state variables */
			x0 = *__SIMD32(px);

			/* Perform the multiply-accumulates */
			acc1 = __SMLALDX(x1, c0, acc1);

			/* pack state variables */
#ifndef ARM_MATH_BIG_ENDIAN
			x1 = __PKHBT(x0, x2, 0);
#else
			x1 = __PKHBT(x2, x0, 0);
#endif

			/* Perform the multiply-accumulates */
			acc3 = __SMLALDX(x1, c0, acc3);
		}

		/* The results in the 4 accumulators are in 2.30 format.  Convert to 1.15 with saturation.
		 ** Then store the 4 outputs in the destination buffer. */

#ifndef ARM_MATH_BIG_ENDIAN

		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc0 >> 15), 16), __SSAT((acc1 >> 15), 16), 16);

		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc2 >> 15), 16), __SSAT((acc3 >> 15), 16), 16);

#else

		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc1 >> 15), 16), __SSAT((acc0 >> 15), 16), 16);

		*__SIMD32(pDst)++ =
		    __PKHBT(__SSAT((acc3 >> 15), 16), __SSAT((acc2 >> 15), 16), 16);

#endif /*      #ifndef ARM_MATH_BIG_ENDIAN       */

		/* Advance the state pointer by 4 to process the next group of 4 samples */
		pState = pState + 4;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = blockSize % 0x4u;

	while(blkCnt > 0u) {
		/* Copy two samples into state buffer */
		*pStateCurnt++ = *pSrc++;

		/* Set the accumulator to zero */
		acc0 = 0;

		/* Use SIMD to hold states and coefficients */
		px = pState;
		pb = pCoeffs;

		tapCnt = numTaps >> 1u;

		do {
			acc0 += (q31_t) * px++ * *pb++;
			acc0 += (q31_t) * px++ * *pb++;
			tapCnt--;
		} while(tapCnt > 0u);

		/* The result is in 2.30 format.  Convert to 1.15 with saturation.
		 ** Then store the output in the destination buffer. */
		*pDst++ = (q15_t)(__SSAT((acc0 >> 15), 16));

		/* Advance state pointer by 1 for the next sample */
		pState = pState + 1u;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* Processing is complete.
	 ** Now copy the last numTaps - 1 samples to the satrt of the state buffer.
	 ** This prepares the state buffer for the next function call. */

	/* Points to the start of the state buffer */
	pStateCurnt = S->pState;

	/* Calculation of count for copying integer writes */
	tapCnt = (numTaps - 1u) >> 2;

	while(tapCnt > 0u) {
		*pStateCurnt++ = *pState++;
		*pStateCurnt++ = *pState++;
		*pStateCurnt++ = *pState++;
		*pStateCurnt++ = *pState++;

		tapCnt--;

	}

	/* Calculation of count for remaining q15_t data */
	tapCnt = (numTaps - 1u) % 0x4u;

	/* copy remaining data */
	while(tapCnt > 0u) {
		*pStateCurnt++ = *pState++;

		/* Decrement the loop counter */
		tapCnt--;
	}
}


#endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */

#else /* ARM_MATH_CM0 */


/* Run the below code for Cortex-M0 */

void arm_fir_q15(
    const arm_fir_instance_q15* S,
    q15_t* pSrc,
    q15_t* pDst,
    uint32_t blockSize)
{
	q15_t* pState = S->pState;                     /* State pointer */
	q15_t* pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
	q15_t* pStateCurnt;                            /* Points to the current sample of the state */



	q15_t* px;                                     /* Temporary pointer for state buffer */
	q15_t* pb;                                     /* Temporary pointer for coefficient buffer */
	q63_t acc;                                     /* Accumulator */
	uint32_t numTaps = S->numTaps;                 /* Number of nTaps in the filter */
	uint32_t tapCnt, blkCnt;                       /* Loop counters */

	/* S->pState buffer contains previous frame (numTaps - 1) samples */
	/* pStateCurnt points to the location where the new input data should be written */
	pStateCurnt = &(S->pState[(numTaps - 1u)]);

	/* Initialize blkCnt with blockSize */
	blkCnt = blockSize;

	while(blkCnt > 0u) {
		/* Copy one sample at a time into state buffer */
		*pStateCurnt++ = *pSrc++;

		/* Set the accumulator to zero */
		acc = 0;

		/* Initialize state pointer */
		px = pState;

		/* Initialize Coefficient pointer */
		pb = pCoeffs;

		tapCnt = numTaps;

		/* Perform the multiply-accumulates */
		do {
			/* acc =  b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] */
			acc += (q31_t) * px++ * *pb++;
			tapCnt--;
		} while(tapCnt > 0u);

		/* The result is in 2.30 format.  Convert to 1.15
		 ** Then store the output in the destination buffer. */
		*pDst++ = (q15_t) __SSAT((acc >> 15u), 16);

		/* Advance state pointer by 1 for the next sample */
		pState = pState + 1;

		/* Decrement the samples loop counter */
		blkCnt--;
	}

	/* Processing is complete.
	 ** Now copy the last numTaps - 1 samples to the satrt of the state buffer.
	 ** This prepares the state buffer for the next function call. */

	/* Points to the start of the state buffer */
	pStateCurnt = S->pState;

	/* Copy numTaps number of values */
	tapCnt = (numTaps - 1u);

	/* copy data */
	while(tapCnt > 0u) {
		*pStateCurnt++ = *pState++;

		/* Decrement the loop counter */
		tapCnt--;
	}

}

#endif /* #ifndef ARM_MATH_CM0 */




/**
 * @} end of FIR group
 */
